#include <iostream>
using namespace std;

class Circle
{
public:
	//写法1:
	//Circle(float _r):pi(3.14),r(_r)
	//{
		//cout<<"构造函数被调用"<<endl;
	//}
private:
	//写法2:
	const float pi=3.14; //圆周率
	float r; //半径
};

int main()
{
	//Circle c1(1.2);
	Circle c1;
}